CANKER. 955 



It is generally advisable to give some opening medicine, and 

 attend to the general health and exercise. 



CANKER. 



Canker of the foot is apt to supervene in cases of neglected or 

 badly treated thrush, quittor, or puncture, and often follows bad 

 cases of grease. It is most common in heavy draught-horses, 

 that are kept in damp, filthy stables, and is most prevalent about 

 large cities. 



Symptoms. In this disease we find a morbid state of the 

 sensitive sole and frog, and instead of sound, healthy horn, fun- 

 gus-excrescences are thrown out, with an offensive acrid discharge. 

 "When aggravated, the whole becomes cov- 

 ered with a growth of fungus, which are 

 like shreds of leather in appearance, with a 

 great tendency to spread over or underrun 

 the sole, separating the horny from the sen- 

 sitive parts. It is very difficult to get the 

 horn to grow again. 



Treatment. In no case is so much pa- 

 tience required as in canker, in fact, it is FIG. 820. The foot, 

 generally considered as incurable, from the Bowing canker, 

 difficulty experienced in suppressing the fungus, and getting the 

 horn to grow again. All loose and detached horn must be care- 

 fully removed, so as to give free vent to the irritating matter. 

 As much of the fungus as may seem practicable, without much 

 bleeding, should be removed by the knife or cautery, and followed 

 up by some escharotic, such as acetate or sulphate of copper, ni- 

 trate of silver, butter of antimony, or sulphuric acid. Whatever 

 caustic is used, it must be applied every day ; for if neglected for 

 one day, it is apt to underrun the sole, and may lose more than it 

 will regain in a week. Firm pressure is very beneficial, and 

 should be constantly applied by means of tow, firmly impacted, 

 and retained by means of slips of wood or hoop-iron slid under 

 the shoe, and the foot must be kept perfectly dry. 



The caustic may be occasionally changed. To destroy the 

 fcetor, chloride of zinc or chloride of lime may be dusted on, or 

 even occasional dressings of dry lime will be useful. With a 

 dressing of tar, in which verdigris and nitric acid, two drachms 



